In order to hold a circular semiconductor wafer (hereinafter, it is referred to as a “wafer” simply) for example as a substrate that is an exposed target, what we call a pin-chuck type of wafer holder in which three lift pins (center pins) for example that is capable of being lifted up and down (going up and down) for carrying a wafer are disposed between many pin-shaped small protruding parts is used by an exposure apparatus such as what we call a stepper or a scanning stepper that is used in a photolithography process for manufacturing an electronic device (a micro device) such as a semiconductor element. Moreover, a SEMI standards (Semiconductor Equipment and Materials International standards) for a diameter of the wafer becomes larger at a rate of 1.25 times to 1.5 times per every several years to be 125 mm, 150 mm, 200 mm and then 300 mm.
The lift pin that is placed in the conventional wafer holder is a bar-shaped component in which a size of its tip part that contacts with the wafer is approximately same as a size of a lower part below the tip part, and an exhaust hole for vacuum suction using suction force that is generated at a negative pressure region is formed at a center portion thereof (for example, refer to a Patent Literature 1).